Various portable devices are provided with two or more parts that are moveable in relation to each other. Depending on the size of the device, the length of a movement and the mass of moving parts, substantial strain may be applied to the mechanism that keeps the parts movably together. There are various technical solutions such as using snug fitting or friction hinging hinged parts, moving a clamp along an axle, rotating a fan with a geared-up speed and squeezing viscous or hydraulic fluid through tight gaps so as to absorb kinetic energy into heat that is dissipated out of the device. However, portable devices such as clam shell formed mobile telephones present a particularly difficult environment in which the known techniques suffer from a number of drawbacks. The dampening mechanisms in such devices are typically inadequately dampening, noisy, fragile, heavy, bulky, complex i.e. difficult to manufacture and prone to malfunction. Hence, reasonably small mechanisms tend to be either expensive or to have too short a life time to endure the harsh operating environment. Namely, mobile phones are often exposed to dropping on a floor in cold and hot environments, squeezing in pocket, use as stress toys and so on. While the manufacturers of mobile phones can guide how to properly use mobile phones and protect them from damage by careful operation and storage, the users often take shortcuts or simply do not bother to avoid malfunction. Yet, when problems arise, the manufacturers are usually asked to repair any faults on their account.